156 S. B. Buckley on North American Formicidse. 



This is the common wood ant, which extends from New England to 

 Texas. It is quite variable in size. Our measurements are from the 

 largest specimens. 



5. Formica gnava, n. sp. 



Female. Length 0.35 inch. — Black or brownish-black, margins of 

 the segments of the abdomen, and also the legs, pale yellow or hyaline; 

 head small, triangular, depressed and flattened above; eyes very large, 

 prominent, elliptical, lateral, and behind the middle of the head; ocelli 

 3, prominent and at top of the occiput; clypeus raised and oval; 

 prothorax large, wider than head, rounded above, subcompressed at 

 the sides, its posterior part widest; mesothorax small, raised as high as 

 the prothorax, rounded above, and with a slight depression between it 

 and the metathorax, which is short, and sub truncate; scale wedge- 

 shaped, vertical ; abdomen large, broad ovate ; wings extending beyond 

 the abdomen, with one marginal, two submarginal, and one discoidal 

 cells. Otherwise like the worker. 



Male. Length 0.29 inch. — Thorax but little wider than the 

 head ; abdomen ovate, short. Otherwise like the female. 



Worker. Length 0.18 inch. — Smooth throughout; head, thorax, 

 and legs yellowish-red ; abdomen black, or piceous ; when first caught 

 or seen in their cells, the whole seems to be of a bronze color ; head 

 ovate, rounded above, below and behind, with a slight depression at the 

 base of the clypeus, which is subcarinated ; antennae long, filiform and 

 •slightly enlarged towards their apical joints; mandibles large, short, 

 strangulated in the middle, then curved inwards, and widened, 7-tooth- 

 ed; eyes large, subelliptical, lateral, and a little behind the middle of 

 the head, near the upper surface ; prothorax little more than half the 

 width of the head, rounded above and enlarged anteriorly; mesothorax 

 depressed, inclined back, with a slight strangulation between it and 

 metathorax; metathorax large, widest in the middle; scale large, 

 wedge-shaped, and slightly inclined forwards; abdomen ovate; legs 

 long. 



Hah. — Central Texas; Washington, D. C; Naples, New York; 

 Connecticut, (Norton). 



Very active and brave ; bites sharply, and emits a strong odor of 

 formic acid. Has cells in the ground, sometimes to the depth of two 

 or more feet, forming small mounds with the excavated earth. Is soli- 

 tary in foraging, scattered here and there over the surface of the 

 ground. 



